1. Field of the Invention
The present invention relates to a photoelectric conversion apparatus and an imaging system using the same.
2. Description of the Related Art
Japanese Patent Application Laid-Open No. 2002-320146 describes that, in a photoelectric conversion apparatus, by adding up or averaging pixel signals included at least two columns of pixels and by outputting the result as an image signal of each pixel, skipping for reducing the number of signals to be read out is performed. In the above-described literature, a configuration in which a pixel mixing switch element for switching connection or disconnection is provided between inverting input terminals of operational amplifiers of at least two columns of amplifier circuits is described. By turning on the pixel mixing switch, the signals from at least two columns of pixels are added up or averaged. In this case, since the signal added up or averaged is output as a signal at a pixel position after skipping, a sampling frequency does not lower. Therefore, it is described that deterioration of resolution can be prevented, and occurrence of folding noises can be prevented, and a good quality image can be obtained.
However, a cycle of the adding up or averaging performed in the photoelectric conversion apparatus described in the Literature is singular, and a photoelectric conversion apparatus operating in a plurality of horizontal adding up or horizontal averaging modes with different adding up and averaging cycles is not discussed. If more pixel mixing switch elements for connecting or disconnecting a plurality of columns of amplifier circuits are added to the photoelectric conversion apparatus in the above-described Literature in order to realize the plurality of horizontal adding up or horizontal averaging modes with different adding up or averaging cycles, a circuit configuration and a layout of the amplifier circuit becomes complicated. In such a configuration, an image quality is expected to deteriorate due to an influence of crosstalk.